Buggy code:
public class ViewsPreferencePage extends PreferencePage implements IWorkbenchPreferencePage { private Button editorTopButton ; private Button editorBottomButton ; private Button viewTopButton ; private Button viewBottomButton ; private ColorFieldEditor errorColorEditor ; private ColorFieldEditor hyperlinkColorEditor ; private ColorFieldEditor activeHyperlinkColorEditor ; private int editorAlignment ; private int viewAlignment ; private static final String EDITORS_TITLE = WorkbenchMessages . getString ( "ViewsPreference.editors" ) ; private static final String EDITORS_TOP_TITLE = WorkbenchMessages . getString ( "ViewsPreference.editors.top" ) ; private static final String EDITORS_BOTTOM_TITLE = WorkbenchMessages . getString ( "ViewsPreference.editors.bottom" ) ; private static final String VIEWS_TITLE = WorkbenchMessages . getString ( "ViewsPreference.views" ) ; private static final String VIEWS_TOP_TITLE = WorkbenchMessages . getString ( "ViewsPreference.views.top" ) ; private static final String VIEWS_BOTTOM_TITLE = WorkbenchMessages . getString ( "ViewsPreference.views.bottom" ) ; private static final String NOTE_LABEL = WorkbenchMessages . getString ( "Preference.note" ) ; private static final String APPLY_MESSAGE = WorkbenchMessages . getString ( "ViewsPreference.applyMessage" ) ; private Group createButtonGroup ( Composite composite , String title ) { } protected Control createContents ( Composite parent ) { Font font = parent . getFont ( ) ; WorkbenchHelp . setHelp ( parent , VIEWS_PREFERENCE_PAGE ) ; IPreferenceStore store = WorkbenchPlugin . getDefault ( ) . getPreferenceStore ( ) ; editorAlignment = store . getInt ( EDITOR_TAB_POSITION ) ; viewAlignment = store . getInt ( VIEW_TAB_POSITION ) ; Composite composite = new Composite ( parent , SWT . NONE ) ; composite . setLayoutData ( new GridData ( ( ( GridData . VERTICAL_ALIGN_FILL ) | ( GridData . HORIZONTAL_ALIGN_FILL ) ) ) ) ; composite . setFont ( font ) ; GridLayout layout = new GridLayout ( ) ; layout . marginWidth = 0 ; layout . marginHeight = 0 ; layout . verticalSpacing = 10 ; composite . setLayout ( layout ) ; createEditorTabButtonGroup ( composite ) ; createViewTabButtonGroup ( composite ) ; Composite messageComposite = new Composite ( composite , SWT . NONE ) ; GridLayout messageLayout = new GridLayout ( ) ; messageLayout . numColumns = 2 ; messageLayout . marginWidth = 0 ; messageLayout . marginHeight = 0 ; messageComposite . setLayout ( messageLayout ) ; messageComposite . setLayoutData ( new GridData ( GridData . HORIZONTAL_ALIGN_FILL ) ) ; messageComposite . setFont ( font ) ; final Label noteLabel = new Label ( messageComposite , SWT . BOLD ) ; noteLabel . setText ( ViewsPreferencePage . NOTE_LABEL ) ; noteLabel . setFont ( JFaceResources . getBannerFont ( ) ) ; noteLabel . setLayoutData ( new GridData ( GridData . VERTICAL_ALIGN_BEGINNING ) ) ; final IPropertyChangeListener fontListener = new IPropertyChangeListener ( ) { public void propertyChange ( PropertyChangeEvent event ) { if ( BANNER_FONT . equals ( event . getProperty ( ) ) ) { noteLabel . setFont ( JFaceResources . getFont ( BANNER_FONT ) ) ; } } } ; JFaceResources . getFontRegistry ( ) . addListener ( fontListener ) ; noteLabel . addDisposeListener ( new DisposeListener ( ) { public void widgetDisposed ( DisposeEvent event ) { JFaceResources . getFontRegistry ( ) . removeListener ( fontListener ) ; } } ) ; Label messageLabel = new Label ( messageComposite , SWT . NONE ) ; messageLabel . setText ( ViewsPreferencePage . APPLY_MESSAGE ) ; messageLabel . setFont ( font ) ; <START_BUG> Label spacer = new Label ( composite , SWT . NONE ) ; <END_BUG> Group colorComposite = new Group ( composite , SWT . NONE ) ; colorComposite . setLayout ( new GridLayout ( ) ) ; colorComposite . setText ( WorkbenchMessages . getString ( "ViewsPreference.ColorsTitle" ) ) ; colorComposite . setFont ( font ) ; GridData data = new GridData ( ( ( GridData . GRAB_HORIZONTAL ) | ( GridData . FILL_HORIZONTAL ) ) ) ; data . horizontalSpan = 2 ; colorComposite . setLayoutData ( data ) ; Composite spacingComposite = new Composite ( colorComposite , SWT . NONE ) ; spacingComposite . setLayout ( new GridLayout ( ) ) ; spacingComposite . setFont ( font ) ; errorColorEditor = new ColorFieldEditor ( JFacePreferences . ERROR_COLOR , WorkbenchMessages . getString ( "ViewsPreference.ErrorText" ) , spacingComposite ) ; errorColorEditor . setPreferenceStore ( doGetPreferenceStore ( ) ) ; errorColorEditor . load ( ) ; hyperlinkColorEditor = new ColorFieldEditor ( JFacePreferences . HYPERLINK_COLOR , WorkbenchMessages . getString ( "ViewsPreference.HyperlinkText" ) , spacingComposite ) ; hyperlinkColorEditor . setPreferenceStore ( doGetPreferenceStore ( ) ) ; hyperlinkColorEditor . load ( ) ; activeHyperlinkColorEditor = new ColorFieldEditor ( JFacePreferences . ACTIVE_HYPERLINK_COLOR , WorkbenchMessages . getString ( "ViewsPreference.ActiveHyperlinkText" ) , spacingComposite ) ; activeHyperlinkColorEditor . setPreferenceStore ( doGetPreferenceStore ( ) ) ; activeHyperlinkColorEditor . load ( ) ; return composite ; } private void createEditorTabButtonGroup ( Composite composite ) { } private void createViewTabButtonGroup ( Composite composite ) { } protected IPreferenceStore doGetPreferenceStore ( ) { } public void init ( org . eclipse . ui . IWorkbench workbench ) { } protected void performDefaults ( ) { } public boolean performOk ( ) { } }

Fix:
new Label ( composite , SWT . NONE ) ;